MMM-AlexaPi Button trigger

I am trying to get a button trigger to work with this module, but no success.
The push button is connected to GPIO16, wich is the native button 12,
and I changed the config of AlexaPi to allow for this button trigger.
No success !
Actually this is an AlexaPi problem and not MMM-AlexaPi,
but if someone can show me a correct AlexaPi config, that would be great.
Thanks.